BACKGROUND: Endometriosis is a common gynecologic disorder with enigmatic etiopathogenesis and is characterized by tumor-like biological behaviors. Recently, circular RNAs (circRNAs) have attracted considerable attention because they exert very important functions in the progression of human cancers. However, little is known about the functions and molecular mechanism of circRNAs in endometriosis.

MATERIAL AND METHODS: A total of 20 patients with ovarian endometriosis and 4 normal endometrium from women free of endometriosis were included in this study. Ectopic endometrium tissues and paired eutopic endometrium tissues were collected from ovarian endometriosis patients. We assessed the expression profiles of circRNAs in endometriosis by microarray analysis. Expression of selected circRNAs in those tissues was detected by quantitative real-time PCR (qRT-PCR). Based on the target prediction, we constructed a circRNA-miRNA-mRNA competing endogenous RNA (ceRNA) network and elucidated circRNAs through Kyoto Encyclopedia of Genes and Genomes and Gene Ontology analyses.

RESULTS: We detected 2237 circRNAs, differentially expressed among 3 groups, and then found 8 circRNAs that may be involved in the epithelial-mesenchymal transition process. The qRT-PCR validation suggested that circ_103470 and circ_101102 matched the microarray results. The functional analysis revealed 17 pathways, such as the mTOR signaling pathway, the Hippo signaling pathway, and the HIF-1 signaling pathway, which may be associated with the pathogenesis and development of endometriosis.

CONCLUSIONS: In general, our results suggest that 2 downregulated circRNAs (circ_103470 and circ_101102) may regulated epithelial-mesenchymal transition in endometriosis via miR-141-5p, which may be a promising therapeutic target in the future.

Keywords: Endometriosis